Shock absorber



Jan, 26, 111932. J. H. HUNT 1,842,831

SHOCK ABSORBER Filed Nov.25, 1929.-

3mm/co4:

fo/m ffunz Patented Jan. 26, 1932 Nirno 'STATES PATENT folflricr 'JOHN fn. HUNT, 'or 'DETROIT, :MICH/IGAN, AssmNoR lro .DELCO -imonuc'rs -icoRroRAm1oN, Eor DAYTON, OHIO, A CORPORATION F .DELAWARE snoek ABSORBER Application mea November 23, 1929. 'serii No. 469;264.

yEhis invention 'relates to improvements 'in hydraulic. shock absorbers.

It isamon'g'the Objects ofthe present invention to provide an hydraulic shock ab 5,4 sorber adapted to control gboththe compression and rebound movements 'of 'vehicle springs.

Another object 'of'thelpresent invention is to provide a v`shock 'absorber 1in v.which all of 1o the fluid control devices :are carried `by the fluid v displacement member.

Further objects' and'advantages Offthe present invention will bela'pparent from the following description, reference beingv had to the accompanying drawings,whereinapreferred embodiment of one form oft'he present Ainvention is clearly` shown.

Inthe drawings Fig. 1 iis a .fragmentary side view of 'a vehicle chassis, 'having a -shockabsorber .em-

bodying thepresentfinvention attached there to.

Figi?. is'alongitudin'al sectional view-taken through the center of the shock'absorber.

Fig. 3 is-a sectional 'view .of theffluid displacement member taken subst'antiallyalong the line 3-3 of Fig.l2, the Operating'member therefor being omitted orthe sake of clearness.

Fig. 4 is an end view ofthe'luid'displacement member.

Referringto the drawings, the numeral 20 designates the `frame of the vehicle having vehicle springs 2l hingedly secured thereto, which springsV support the lframe upon the vehicle axle 22.

The shock absorber comprises a casing 23 presenting a fluidreservoir 24 and a cylinder 25. The fluid reservoir has anopening 426 which is closed and sealed by ia cover 27 provided with agaslret 28 and secured to the casing 23 by screws 29. The open ends of the cylinder portion of the casing 23 are each provided with interior screw threads adapted to receive the end cover members 30 and 3l respectively.

1Within the cylinderv portion 250i the casing there is provided a liiuid displacement member 40 forming' a compression chamber at each end of the cylinder. One compression `c'vharnberis designated bythe numeral 4l, the other by fthe numeral 42. yIn eaclrend of the 1pis`to1i-40therelisprovided a valve chamber,

one y'being designated lby the numeral 43, the

otherby'thenumeral 44. The outer ends of these valve-chambers terminatein the 'respectiveend'surfaces O't'he'piston 40 sothat valve chamber 43 maybe said toopen into the compression chamber'4l, while 'valve chamber 44 opens intofthe'compression chamber yThe designated'by the'numeral'45, and the valve seat forthe valveichamber 44 b ythemimei|- `al 46. A valve "47 'is contained within 'the valve chamber 4'3and asimilar valve '48 inthe valve "chamber 44. Valve 47 is `maintained against its seat member 45 by 'a spring 49 interposed between said valve 47 andthe closed endofthevalvechamber 43. A simi- 'lar spring :5.0, withinit'he .valve chamber 44, yield'ably' maintains valve 48 'in engagement Withgits valve seat member 46. A duct l51 has its one end terminating in the valve chamber '43, the .other Jin the opposite end surface of'thepi'ston'which y'forms one wall ofthe 'compression chamber "42. A similar duct 52 terminates 'atone `end`in the valve chamber'44,^theother endlinthe opposite end of the piston which forms one wall ofthe compression chamber 41. "Both ducts 51 and 52 are normally Aclosed at vtheir respective valve -"charnber ends by the respective valves 47. and 48.

'pThe valves .just described Vform the compression vrelease valves ofthe shock absorber` and-are adapted, at Aproper fluid pressures within .their .respective compression chambersstogprovide'arestricted flow of-.fluidfrom saidrespeetivelcompression chambers to the compression chamber at the Opposite-end of the cylinder, thus, 'compression-.chamber 41 maydischarg'epast 'the valve 47 through duct 51 into 'the compression chamber 42 in response to `Va proper vrfluid pressure within the compression 'eh-amber 41, 'while compression chamber '42m'ayata proper pressure discharge through duct 52 into the compression chamber 41.

Fluid leaking past the pistons, or from any other supposedly sealed portion of the shock absorber, would gradually deplete the supply of fluid within the compression chambers 41 and 42 so that eventually effective operation of the shock absorber would be materially affected. In order to compensate for such fluid leaks, each end` of the piston 40 is provided with a fluid replenishing valve. The piston has a recess 59 intermediate the ends thereof which receives piston operating aim 60 and which is at all times in communication with the fluid reservoir 24. A duct or passage 61 in the piston 40 provides communication between the recess 59 and the compression chamber 42, while a similar duct 62 provides communication between the compression chamber 41 and said intermediate recess 59. Each passage 61 and 62 has an enlarged portion adjacent its respective piston end forming a valve chamber, the valve chamber opening into the compression chamber 42 being designated by the numeral 63, the chamber opening into compression chamber 41 being designated by the numeral 64. A tapered shoulder 65 is provided in the duct 61, while a similar tapered shoulder 66 is provided in the duct 62. These tapered shoulders form valve seats for the respective ball check valves 67 and 68. Ball check valves 67 and 68 are maintained in yieldable lengagement with their respective valve seats by springs 69 and 70 respectively.

The piston operating arm 60 is anchored upon a shaft which is journalled within bearings provided by the casing 23, said shaft having one end extending outside the casing and being provided with the shock absorber operating arm 81, the free end of which is swivelly secured to one end of the link rod 82. The opposite end of the link rod 82 is secured to a member 83 which is anchored to the axle 22 by the clamping member 84.

The device functions in the following manner:

lVhen the wheels (not shown) strike an obstruction in the roadway, springs 21 are flexed toward the frame 20, resultin iny a clockwise movement of the arm 81 Ey the link rod 82. Arm 81 rotating clockwise will cause a similar rotating movement of the shaft 80 and its attached piston operating arm 60 so that, as the springs 21 move toward the frame 20, the piston 4() will be moved toward the left as regards Fig. 2 and consequently, if compression chamber 42 needs its fluid supply to-be replenished, fluid will flow from the reservoir 24 into the intermediate recess 59 of the piston and then through the duct 61 past the valve 67 through the valve chamber 63 into the compression chamber 42. Movement of the piston 40 toward the left will exert pressure upon the fluid within the compression chamber 41 which, if attaining a proper value, will move the valve 47 from the valve seat 45, against the effect of its spring 49 and will thus establish a restricted flow of fluid from the chamber 41 through the valve seat member 45 past the valve 47 through duct 51, exhausting into the compression chamber 42. The restriction to the flow of fluid from the compression chamber 41vby valve 47, will resist the movement of sirable ars and jolts being transmitted to the r frame of the vehicle. The present device retards the movement of the spring toward the normal, unflexed position for, as the springs begin to move away from the frame 20, the link rod 82 will move the shock absorber operating arm 81 in a counter-clockwise rotation, resulting in a similar rotation of the shaft 8O and arm 60 and thus a clockwise movement of the piston 40 toward the right. Now the replenishing valve 68 may become eifective to compensate for fluid losses if there are any in 'the chamber 41. hovement of the piston 40 toward the right will cause the fluid within the chamber 42 to move the valve 48 from its seat as soon as the fluid pressure in the compression chamber 42 reaches a predetermined value, at which time a restricted flow is established from the fluid chamber 42 past the valve 48 through duct 52 linto the compression chamber 41. 'i

The restriction by the valve 48 to the flow of fluid from the chamber 42 will resist the movenient of the piston 40 toward the right and thus will be resisted the movement of the springs 21 toward their normal unflexed position whereby rebounding movements of the spring are substantially eliminated and thus the resulting jars and jolts are substantially avoided.

The present invention provides a device of simple structure and design and inasmuch as all fluid flow controlled valves are carried by the piston, it may readily be seen that the pis ton assembly may be completely tested and 1 checked before it is finally assembled into the shock absorber, thus facilitating production of an efficient operating shock absorber with a minimum expenditure of time.

Vhile the form of embodiment of the presi What is claimed is as follows:

l. A shock absorber comprising, in combination, a casing presenting a Huid reservoir and a cylinder a piston in said cylinder forming a compression chamber at each end thereof; means for reciprocating said piston; valved ducts in the piston adapted to establish communication between the compression chambers in response to predetermined fluid pressures within the respective chambers; and valved ductsI in the piston adapted to establish communication between the respective compression chambers and the fluid reservoir to replenish the fluid supply in said chambers.

2. A shock absorber comprising, in combination, a casing presenting a fluid reservoir and a cylinder; a piston in said cylinder forming a compression chamber at each end thereof; means for reciprocating` said piston; two valve chambers at each end of the piston; a duct connecting the one valve chamber at each end of the piston with the compression chamber at the opposite end of the piston; a duct connecting each other valve chamber at each end of' the piston with the fluid reservoir; a spring-loaded valve in the one valve chamber at each end of the piston, adapted to establish a restricted flow of uid from the respective compression chamber at that end of the piston, through its duct, to the chamber at the other end of the piston, as the piston moves toward the end of the cylinder adjacent the respective valve and as a proper fluid pressure is attained; and a spring-loaded valve in the other valve chamber at each end of the piston, adapted in response to the movement of the piston away from the end of the cylinder adjacent the respective valve, to establish a replenishing flow of fluid from the fluid reservoir into the respective compression chamber with which said valve communicates.

3. A shock absorber comprising, in combination, a casing presenting a Huid reservoir and a cylinder; a piston in said cylinder forming a compression chamber at each end thereof; means for reciprocating said piston; a pressure release and an intake chamber at each end of the piston, each pressure release chamber communicating separately with both compression chamers and each intake chamber with a respective compression chamber and the fluid reservoir; a valve in each pressure release chamber adapted to establish a restricted flow of fluid through said chamber only in response to a proper fluid pressure in its respective compression chamber; and a valve in each intake chamber adapted to establish a replenishing fluid flow from the fluid 50 reservoir into the respective compression chambers as the piston moves to increase the cubical contents of said chambers.

In testimony whereof I hereto af'tix my signature.

e5 JOHN H. HUNT. 

